The invention applies to all fields for which a strip of material has to be conveyed along a production line. More particularly, the invention relates to the field of the production of food pots, for example yoghurt pots.
In this field, it is in fact necessary to convey a strip of material, more often than not plastic material, along the production line to stations for forming pots from the strip of material.
One known system for conveying such a strip of material comprises a bearing means for the strip of material, one or more link chains, of which certain links include a lateral plate provided with a means for driving the strip of material, and a counter-bearing means for pressing the chain against the bearing means on which the strip of material bears.
The bearing means consists of a roll with a circumferential groove. The means of driving the strip of material provided on certain links is formed by a spike arranged at the centre of the link. The counter-bearing means consists of an anvil which thus has a planar face on which the link bears.
When a strip of material is positioned between the roll and the link chains, the spikes penetrate into the strip of material as the latter moves. The penetration of the spikes into the strip of material is assisted by the anvil which presses the chain against the roll, the spikes penetrating into the strip of material and then fitting into the groove provided in the roll.
The system generally comprises two chains with spikes arranged either side of the roll in order for each side of the strip of material to be driven by the spikes.
One known system as described hereinabove is, for example, represented in FIGS. 1 to 3. FIG. 1 is a diagram representing, from a side view, a system for conveying a strip of material according to the prior art. FIGS. 2 and 3 represent enlarged views of the system of FIG. 1 showing the area of penetration of the spikes into the strip of material to be conveyed, these figures illustrating two positions of the strip of material relative to the chain.
In these FIGS. 1 to 3, the strip of material 20 to be conveyed, the roll 10 forming bearing means for the strip of material 20, the link chain 11 with spikes and the anvil 12 forming counter-bearing means for the chain can be distinguished.
The path of the chain 11 is represented by the broken lines 110. The link chain 11 is returned between the roll 10 and the anvil 12 by virtue of at least one return wheel R. The chain 11 is thus brought into position facing the strip of material by the return wheel R.
The strip of material 20 is conducted roughly in a straight line by means referenced 14, 15.
The chain 11 meets the strip of material 20 to be conveyed along the production line at a counter-bearing area where the spikes 111 of the chain can penetrate into the strip of material 20. This counter-bearing area is situated between the roll 10 and the anvil 12.
Such a system is effective inasmuch as it allows the strip of material to be effectively conveyed along the production line, but it also has a number of drawbacks.
Firstly, this system comprises numerous parts in order to operate, which generate a relatively significant bulk. In particular, it provides for a return wheel R for the chain arranged at a distance from the anvil 12 of the chain 11. By positioning the return wheel R at a distance from the anvil 12, it becomes possible to position the chain 11 substantially parallel to the anvil and, consequently, arrange the spikes 111 perpendicularly to the anvil to facilitate the penetration of the spikes 111 into the strip of material 20.
Secondly, this system implements an anvil as counter-bearing means for the chain, which forms a wear part which must be regularly changed.
The nature and the quantity of parts involved correspondingly increases the service time needed to change or adjust these parts.
Finally, the spikes 111 provided on the links of the chain 11 have dimensions that are not inconsiderable to ensure their good penetration into the strip of material, and a significant quantity of material is therefore needed to make them.